The first phase of this research project focused on developing an understanding of the current practice behaviours being exhibited by coaches within elite-level English youth football. That is, prior to any further enquiry into this unique setting, it was felt that an investigation should establish, as accurately as possible, the practice behaviours utilised in the coaching of talented youth players. Thus, Study la comprised the contextual validation of a systematic observation instrument (the Elite Youth Football Coaches' Observation Instrument; EYFCOI) that would enable a precise detailing of coaches' practice behaviours to be undertaken that was more holistic than the other observational tools in common use. Subsequently, Study lb used the EYFCOI to carry out an evaluation, over mid-late season, of Under 12, Under 15, and Under 19 coaches' behaviours that found instructional provision to feature prominently within positive learning environments. These behaviours, and players' perceptions in relation to them, were found to be stable throughout the observation period. A significant age group finding, however, was identified in relation to players' perceptions, as younger players were found to have higher levels of enjoyment, exerted effort, and perceived learning than their older peers. Descriptive analysis of the coach behaviour data revealed that coaches of older players provided more frequent verbal instruction, but less frequent demonstrations and questioning strategies. A positive-to-negative feedback ratio of approximately 4: 1 was consistently recorded across the three age groups, with general feedback usage found to dominate over feedback that was informational. Study 2 sought to build on the findings of Study lb by qualitatively investigating the factors that influenced the performance of their role, whilst simultaneously researching players' coaching behaviour preferences. The main findings identified in relation to the factors impacting on coaches' performance of their role included a consistently cited emphasis on developing players, with conflicting opinions expressed in relation to how this is best achieved. The beliefs ranged between the extremes of valuing intense, pressurising, and controlling methods to a much more facilitative approach. Coaches' educational development was found to be primarily achieved through independent reflections. The most significant findings from the focus group interviews with players was a preference for coaches' open questioning usage on the basis that it was most beneficial for learning. Similarly, this same reason was cited for players' desire for feedback to be provided that was specific and informational. The final study assessed the efficacy of an autonomy-supportive coach behaviour intervention that was conducted over a 24-week period in mid-late season. Following an initial baseline period, coaches were supplied with educational support essentially geared towards increasing their usage of open questioning and making specific feedback their dominant feedback type. Support - in the form of quantitative data, video feedback, and behavioural modification strategies - was consistently provided during an intervention period, before being withdrawn post-intervention. The participating coaches were each found to successfully modify their behaviours, although it was found that changes were most effectively realised through coaches' perceived value in the programme of study, their adherence to the programme (reflected most notably in their independently-initiated efforts to achieve behavioural changes), and ultimately, in reaching a behavioural frequency at which the coaches' objectives were best achieved. Overall, the present thesis has extended the knowledge of elite-level English youth football environment, identifying practically-based findings that, it is proposed, can be of use within the development of coach education content and strategies in particular.